Sink mat



FIG. 1 is a top left front perspective view of a sink mat showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a left side elevational thereof; the right side elevational being a mirror image;

FIG. 4 is a front elevational view thereof; the rear elevational view being a mirror image; and,

FIG. 5 is a bottom plan view thereof.

The broken line showing of a center hole in FIGS. 1, 2 and 5 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a sink mat, as shown and described. 